DLL Programmer's Guide for TNS/E Systems

DLLs on a TNS/E System

DLL Programmer’s Guide for TNS/E Systems—527252-006

1-2

Libraries and Symbols

A loadfile exports a symbol when it defines a symbol that can be used by another

loadfile. A loadfile imports a needed symbol when that symbol reference in the

program or DLL is or will be set to the value (address) of a symbol of the same name

exported by another loadfile. Thus, in Figure 1-1, Library K exports Joe and, after H is

loaded, H imports Joe.

In the rest of this document, the term library means a DLL that may be designed for

either public or private use.

Figure 1-1. Symbol Resolution by Binding at Load Time

1300

Lib J

Lib K

Joe()

Call Joe()

Call 16300

Lib L

Lib K

Joe()

Lib J

10000

15000

18000

Four object files after they are loaded

Four object files before they are loaded

Lib L

4000

3000

5000

VST011.vsd